1. Field of the Invention
The present invention relates to electrical connectors and, more particularly, to an electrical connector for connecting a cable having paired wires.
2. Description of the Related Art
Japanese patent application Kokai No. 10-134903 discloses an electrical connector of this type. A cable having a plurality of wires, each pair of which are twisted to prevent the production of noise by an alternating magnetic field, is well known. It is preferred that the twisted condition of paired wires be kept closely to the terminals to be connected although the paired wires must be untwisted for connection.
The above electrical connector employs two members; that is, a guide plate and an arranging member. The guide plate has a plurality of apertures through which paired wires are put. The arranging member has a plurality of apertures through which untwisted wires are put.
In use, a length of outer jacket of a cable is removed. Each pair of twisted wires are put into the aperture of the guide plate. The projected paired wires are untwisted and the straightened wires are put into the apertures of the arranging member. Then, the projected straight wires are connected to the terminals of the connector.
However, the length of the straight wires supported by the arranging member is so large that the impedance at the terminal connection point is diturbed. Also, this connector requires both the guide plate and the arranging member, making it large. Further, it requires two operations to put wires simultaneously through both the small apertures of the two members arranged in the longitudinal direction of the wires. Especially, untwisted wires tend to strike the edges of the apertures, failing passing through the apertures.
Accordingly, it is an object of the invention to provide an electrical connector having only one member for guiding and supporting both paired and straight wires in small length to suppress the impedance disturbance and enabling to insert the paired and straight wires without difficulty.
According to the invention there is provided an electrical connector comprising a housing; a plurality of terminals arranged in the housing and connected to a plurality of paired wires of a cable; a guide member having a plurality of receiving channels for guiding and supporting the paired wires, wherein each of the receiving channels has a wide channel for receiving each of the paired wires, a pair of narrow channels for receiving a pair of untwisted wires of the each paired wire, and a branching channel joining the wide and narrow channels.
In use, a length of the outer jacket of a cable is removed to expose a plurality of paired wires, end portions of which are straightened, and the straightened portions, the paired portions, and the intermediate portions between them are put into the narrow, wide, and branching channels, respectively, of the guide member by pushing them into the channeles in the diametric directions. The single guide member supports both the paired and straight wires, minimizing the number of components, the size of the connector, and the assembling time. The length of the straight wires is so small that the impedance disturbance is minimized and the transition from the paire wires to the straight wires is so even that the electrical characteristics are made uniform.
It is preferred that at least one of the wide, narrow, and branching channels has an engaging shoulder at its edge to prevent the paired or straight wire from coming out of the one channel. The connector may comprise a movable member supported by at least one of the housing and the terminals for rotation between an open position wherein the straight wires projecting from the guide member are inserted into a space between the movable member and the terminals and a closed position wherein the movable member presses the cable against the terminals. It may further comprise a shield case that may be put over the housing when the movable member is at the closed position to cover the housing and the guide member. The shield case may be brought into contact with a wire shield of the cable. The shield case may have a gripping portion that is deformed on a wire shield of the cable.